Geneva drive



A. R. THOMPSON 2,337,359

eansw. mmm nal Filed July 13, 1940 Dec- 21, 1943.

Otigi mvam-on ALBLRTR. THOMPSON ATTORNEY Patented Dec. 21, 1943 GENEVA DRIVE Albert R. Thompson, San Jose, Calif., assignor to Food Machinery Corporation, San Jose, Calif., a corporation of Delaware Original application July 13, 1940, Serial No.

Divided and this application December 7, 1942, Serial No. 468,027

4 Claims. ('01. '14436) The present invention relates to a Geneva drive for translating a continuous rotation into an intermittent rotation.

This application is a division of my co-pend- I04 to thereby lock the star wheel against rotation when it is at rest.

Secured to the gear Hi8 and the cylindrical flange I thereof by means of screws IBM is a ing application, Serial No. 345,335, filed July 13, 5 plate I89 provided with an arcuate face or edge 1940, for Pear preparation machine. 5 I0 which is flush with the peripheral face of the One object of the present invention is to proflange I05. The plate I89 is further provided vide a drive mechanism for translating a contin With an arcuate face or edge Ii! adjacent the uous rotary movement into an accurate interv 99 a adapted o engage e Contact face mittent rotation. 10 NM of the lugs N2 of the star wheel I04 pre- Another object is to provide a Geneva drive V 0 1y e e he p e is further for translating a continuous rotation into inter- Vided W a t Out pOTtiOII intermediate mittent rotation wherein independent rotation of the a c a f es and H! S s 0 p de the Geneva wheel in either direction is prevented. ufli i nt le r n twe n the s H2 n Another bject is t provide a Geneva drive 15 the plate IE9 to permit rotation of the latter relafor translating a continuous rotation into intert to e t r W ee W mittent rotation wherein any back-lash of the m t e above t i e Se that 111 0 0011- Geneva wheel i prevented, tinuous rotation of the drive shaft I02 and drive Other and further objects and advantages of gear IIJI in the direction of arrow 562a, in Fi the present invention will become apparent from gear driver flange 3 and p te 99 the following description and drawing in which: are continuously rotated in,the direction of the Fig 1 i a id View of t Geneva drive of arrow I 69a. During each revolution of the gear the present invention. I00 the driver 99 carried thereby enters one of Fig 2 is an enlarged View f a portion f the the slots I 63, see Fig. 2, rotates the star Wheel Geneva drive shown in Fig 1 illustrating the I04 and shaft II5 60 degrees and leaves said slot Geneva driver and its associated parts in another When the same is in the pesition shown in position From the time the driver 9% leaves said slot until The Geneva drive of the present invention (see it enters the next slot during the continuous Fig. 1) comprises a star or Geneva wheel 5M Totatlon of gear may we 'f Wheel and which is kgyed to a driven Shaft M5 for rotation shaft H5 are at rest. In th s Way, star wheel therewith. The Shaft an; is rotatably mounted i i g mi gg i gfiigz I 7 a mlilggrbeanngs (not shown) in any conven ent tation of shaft '02 and gears ml and mo- The sta wheel HM is provided With six radial s; igg gg giig gg fgfi ggz fg ig :3: slots spaced @T .apart and arcuate 30 spect to the driver 59 that it does not interfere penpheral faces lmermedlajte the a f with the rotation of the Geneva wheel 'IM durc ured to the Star Wheel @dJacem emmg ing rotation of the same by the driver 99. This sldes 3 of each a mg I These locking flange I65 is further so positioned and follugs from f of title Star wheel 40 lows the Geneva driver 99 in such a mannerthat and each or them 15 provided with a contact face the peripheral face of the flange m5 mmtively IIZa. engagessuccessive arcuate faces I06 of the star Rotatablypmounted aflacent the Wheel 5% wheel we following the slots Hi3 engaged by the means Shaft supportefd f bear" driver 99 and thereby locks the star Wheel against e (not shown) 13 a gear which mtemgeshes rotation after the driver at has left the respec- With a drive gear keyed m a drive shait '9 tive slot 53. This locking action is well known Secured to the gear IEO for rotation therewith in the art is a Geneva driver or pin 99 adapted to enter and It Should be noted, however, that when the leave successive slots 503 of the star wheel Hi4 Geneva drive is in the position Shown in Fig 1, upon mt-ation of the gear 5% to thereby efiect i. e., the driver 99 leaving the slot m3 and the intermittent rotation of the star wheel EM and t Wheel #03 has just come to rest, the end 33 shaft I l5 associated therewith. of the locking flange m5 is necessarily at a posi-- The gear it!) is further provided with a cylintion coincident with or siightly below a straight drical locking flange Hi5 adapted to engage the line between the axes or centers of. the shafts arcuate, peripheral faces I08 of the star wheel I58 and H5. This is for the reason that the" star wheel I04 is in motion and cannot be locked against rotation until the driver 99 disengages from the slot I03. This position of the locking flange I05 may becalled the dead center position. When the locking flange is in its dead center position( see Fig. l), the star wheel I04 is not positively locked thereby against counterclockwise rotation, i. e., so far asthe locking flange isconcerned, the star wheel I04 may be rotated a slight distance. in counter-clockwise direction until the outer edge of the end I08 ofthe flange I05 presses against the surface of the arcuate face I06 adjacent the same.

Therefore, when the driven shaft I I5 is under load or operates a mechanism exerting resistance against rotation of the star wheel I04 in clockwise direction, the locking flange I05 cannot pre-' vent a slight counter-clockwise rotation, i. e., backlash, of the star wheel I04 when the looking flangeis at its dead center position, due to the incomplete locking action of the same at this time. Serious disadvantage, due to the backlash of the star wheel I04, as above described, is that no accurate positioning or indexing of the star wheel I04 and driven shaft I I5 is obtained at the moment the driver 99 leaves the slot I03 and the locking flange I05 is at its dead center position. Consequently, heretofore Geneva drives could not be employed in connection with machines wherein an accurate intermittent motio without back-lash, is required.

Continuing now with the description of the operation of the Geneva drive of the present invention, it should be noted that when the driver 99 leaves the slot I03 incident to the cessation of rotation of the star wheel I04 in clockwise direction (see Fig. 1), the arcuate peripheral face III of the plate I09 which rotates with the gear I and driver 09 engages one of the lugs I IZ-adjacentthe same at this time and locks the star wheel I04 in accurately indexed position preventing any back-lash of the same in a counter clockwise direction.

While the gear I00,1ocking flange I05 and plate I09 continue their rotation in the direction of arrow I00d (see Fig. l) the arcuate face III of plate I09 travels past the lug H2 in contact therewith and disengages therefrom only when the locking flange I05 isin engagement with the entire arcuate face I06 of the star wheel I04 adjacent the same. The star wheel is now held in accurately locked position by the engagement of the locking flange 505 with the respective arcuate face I06.

During further rotation of the-gear I00, the driver 99 enters the. next slot 103 When the other end I0'I.of the locking flange I05 is in the positionshown in Fig. 2 and unlocks the star Wheel I04 whereupon the operation of the star wheel I04 repeats in the same manner as described herein.

' It will therefore be seen that the continuous rotation of shaft I02 and gears IOI, and I00 is translated into an accurate intermittent rotation of the star wheel I04 and shaft I I5 and that the star wheel I04 and shaft II5 are held and locked inaccurately indexed position without any possibility of back-lash when the same are at rest.

While I have described a particular embodiment of the present invention, it will be understood that various changes and modifications may be made without departing from the spirit of the present invention and the scope of the appended claims. 7

I means for preventing back-lash of the star wheel.

Having described my invention and in what manner the same may be used, what I claim as new and desire to protect by Letters Patent is:

1. A Geneva drive comprising a rotatable star wheel having a plurality of slots extending radially from the periphery thereof, a rotatable plate provided with a drive pin cooperable with the slots of said star wheel for intermittently rotating the star wheel, and a lug carried by the star wheel adjacent each slot thereof, said plate having an arcuate face whose center is the axis of rotation of the plate and being so arranged that said arcuate face comes into locking engagement with the lug adjacent the slot withwhich the 'drive pin is engaged just as the drive pin leaves the slot.

2. A Geneva drive comprising a rotatable star wheel having a plurality of slots extending radially from the periphery thereof and arcuate peripheral faces intermediate said slots, a rotary support adjacent said star wheel and having an arcuate edge concentric with the center of rotation of the support, a drive pin carried by said support for cooperation with said slots for intermittently rotating the star wheel, a segmental circular locking flange carried by said support for intermittently engaging the arcuate faces of the star wheel for locking said star wheel against rotation during its rest periods, and a plurality of lugs carried by said star wheel in such positions that one of said lugs is engaged by the arcuate edge of said rotary support just as the drive pin terminates cooperation with a slot whereby to lock said star wheel against backlash.

3. A Geneva drive comprising a rotatable star wheel having a plurality of slots extending radially from the periphery thereof and arcuate peripheral faces intermediate said slots, a rotatable driver cooperating with the star wheel and slots thereof for intermittently rotating the star wheel, a segmental circular locking flange rotatable with the driver for rotatively engaging one of the arcuate faces of the star wheel for locking the star wheel against rotation when it is at rest during its intermittent operation, and means for preventing back-lash of the star wheel upon cessation of its rotation including a lug on the star wheel projecting laterally therefrom and a locking plate associated with the driver having an arcuate face engaging said lug at the instant when said star wheel comes to rest.

4. A Geneva drive comprising a rotatable star wheel having a plurality of slots extending radially from the periphery thereof and arcuate peripheral faces intermediate said slots, a rotatable driver cooperating with the star wheel and slots thereof for intermittently rotating the star wheel, a segmental circular locking flange rotatable with the driver for rotatively engaging one of the arcuate faces of the star wheel for looking the star wheel against rotation when it is at rest during its intermittent operation, and

upon cessation of its rotation, said means including a lug on the star wheel positioned adjacent each slot thereof and projecting laterally therefrom and a locking plate associated with the driver and rotatable therewith having an arcuate face defining the arc of a circle about the center of rotation of the driver for engaging said lug instantaneously when said star wheel comes to rest.

ALBERT R. THOMPSON. 

